The most relevant background art in this area known to the inventor is set forth in the previous Technical Description section. It is noted that the personal identification area is extremely active and highly developed at this time. At the heart of most current personal identification number/credit card systems are sophisticated, secure encryption systems, the best known of which is the key-controlled block cipher cryptographic system adopted by the National Bureau of Standards as a Federal Information Processing Standard entitled "Encryption Algorithm for Computer Data Protection". The Standard together with a complete technical description is contained in the publication, "Data Encryption Standard," Federal Information Processing Standard (FIPS), Publication 46, National Bureau of Standards, U.S. Department of Commerce, January 1977. U.S. Pat. No. 3,958,081 specifically discloses a hardware embodiment of an encryption device which fully complies with the above identified standard.